- Preheat oven to 200°C.
- Heat butter in a large frying pan and sauté onion and garlic until soft and fragrant.
- Add flour and cook for 2-3 minutes until the texture is sandy.
- Gradually add hot milk, stirring until smooth and creamy.
- Process or finely chop jalapenos and spinach leaves until very fine then add them to the creamy sauce along with the sour cream and Gouda Cheese.
- Stir until creamy then pour into an oven-proof serving pan or dish. Sprinkle with extra grated Gouda Cheddar and top with a few jalapenos.
- Bake for 10-15 minutes until golden and bubbling.